Brake-shoe



(No Model.)

W. D. S ARGENT. BRAKE SHOE.

No. 555,975. Patented Mar. 10, 1 896.

s MW dag ANDREW B GRANAMFPMOTQ-LIMQWASNINGTON. 0.0

NlTED STATES Fries.

ATENT BRAKE-SHOE.

SPECIFICATION forming part of Letters Patent No. 555,975, dated March10, 1896.

Application filed December 13, 1895. Serial No. 572,05 '7. (No model.)

To all whom it may concern.-

Be it known that I, TILLIAM I). SARGENT, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in Brake-Shoes, of whichthe following is a full, clear, and exact description, referencebeinghad to the accompanying drawings, forming a part of thisspecification.

This invention relates to the class of brakeshoes known in the art asdressing brakeshoes, because, in addition to their function of brakes,they serve the purpose of dressing the entire tread and flange ofcar-wheels in proportion to the wear on said wheels resulting fromcontact with the rails. This class of brake-shoes is exemplified inLetters Patent of the United States No. 523,084, granted to me July 17,1894, upon which my present invention is more especially designed as animprovement.

The primary object of this invention is a brake -shoe which will notonly dress carwheels proportionately to the wear thereof, due to contactwith the rails, so as to 1nai11- tain the tread and flange of the wheelsin uniform and proper condition at all times during their lives, butwill also possess the maximum degree of longevity in service withoutdetriment to the strength or braking quality of the shoe.

A further object is to provide a brake-shoe with a wearing-surface thatshall be practically continuous over the tread and flange of acar-wheel, which will dress with maximum effect those portions of thewheel which do not contact with the rail, and which will dress thoseportions of the wheel that are worn by contact with the rail withproportionate effect and which will yet have a composite metallicwearing-surface, a portion of which is directed to afford a brakingeffect, while the other portion serves to retard the wear of the shoe.

Another object of the invention is a brakeshoe having integral hard andsoft or composite metallic wearingsurfaces, which shall possess in themaximum an exceptional degree of strength, durability, andeffectiveness.

These and such other objects as may hereinafter appear are attained bythe device illustrated in the accompanying drawings, in which- Figure 1is a perspective view of a brake shoe provided with alternate chilledparts and in Fig. 0. ordinary flat brake-shoe. Fig. 0 is .acrosssectional view of a flat brakeshoe, showing a flange on the backthereof; and Fig. '7 is a diagrammatic view illustrating the wear upon awheel and the position of the chilled parts in the brake-shoe withrelation to the wear on the wheel.

In all of the figures, A designates the body portion of the brake-shoe,and B the chilled parts thereof. These chilled parts may be variouslydisposed, and in Fig. 1 I have shown them arranged alternately withopenings 0, one or more of which may be provided as desired. In thiscase the chilled parts extend through all that portion of the shoebetween the openings, as clearly shown in Fig. 1.

In Fig. 3 I have shown anumber of chilled parts with narrow webs I)separating said parts, and in Fig. 5 the webs separating the chilledparts are wider than those shown in Fig. 3. These chilled parts may bemade in many ways, but a common way is to subject parts of the shoe tothe action of a cold piece of metal in the process of casting. Thechilled parts may be of any desired configuration and size, audit willbe understood by those skilled in the art, as well as by others, thatthe number and size, as well as the location and arrangement of thechilled parts with relation to the other parts of the brake-shoe, willvary under different conditions, but the chilled parts are arranged insuch a position with relation to the other parts of the brake-shoe thatthey will be located opposite to that portion of the wheel which is Wornby contact with the rail, and those portions of the wheel which do notcontact with the rail, and therefore are not worn, will be dressed bythe soft parts of the brake-shoe around the chilled parts thereof withmaximum effect.

In Fig. 7 I have shown the preferred location of the chilled parts withrelation to the wear on the wheel. In actual use it will be found thatthe chilled parts of the brakeshoe wear more or less, but they do nothave the dressing effect upon the wheel that is afforded by the otherparts of the brake-shoe. While the soft parts of the brake-shoe wear thewheel by reason of the grinding action afforded by the particles rubbedoff of the shoe the chilled parts form polished surfaces and do not, toany material extent, dress the por tion of the wheel with which theycome in contact. The chilled parts merge into the soft parts of theshoegradually, and the corners thereof are rounded, as at F, whereby thedressing-face of the shoe is gradually enlarged on either side of theline where the wheel is worn the most by the rail.

The foregoing will be clearly understood by referring to thediagrammatic view, Fig. 7, in which G represents the car-wheel; H, therail; I, a portion of the brake-shoe; J the original outline of thecar-wheel, and K the outline showing the ordinary wear upon a carwheelby the rail to which a dressing brakeshoe has not been applied inservice.

That portion of the wheel-tread between the lines a a represents thearea of maximum and practically uniform wear of the rail upon thewheel-tread.

That portion of the wheel-tread between the lines a and b and a and 1)represents the area of proportional wear of the rail upon the tread, theminimum wear being at about the lines I) b. That portion of the treadand flange between the lines Z) c and b a represents the area of no wearupon the wheel by the rail, because these portions of the wheel nevercome in contact with the rail. It is therefore desirable to dress withmaximum wearing effect substantially that portion of the wheel tread andflange included between the lines I) c and b c, to dress with minimumwearing effect that portion of the wheel-tread between the lines a anda, and to dress with a proportionate effect from the maximum to theminimum that portion of the wheel tread and flange between the lines aZ) and a b. That portion of the shoe indicated by the letter d isintended to illustrate the merging of the chilled portion of thebrake-shoe into the soft or unchilled portion thereof, and while I haveshown in this view and in the other views a comparatively sharp line ofdemarcation between the chilled and unchilled or soft portions of theshoe, in practice no such line does or can exist, as the eifect of thechill will extend, in a rapidly-lessening degree, from the desiredoutlines of the chilled portion into the soft portion, so that thewearing-surface of my brake-shoe, in point of fact, is of compositemetal of three degrees of hardness, the hardest being over the area ofmaximum wear, the softest being over the area of minimum wear and theintermediate being over the area of proportionate wear of the rail uponthe wheel.

I am aware that there are many different constructions in the art whichpropose or attempt to provide for the uniform dressing of wheels asidefrom my patented invention hereinbefore referred to, but so far as I amaware it is broadly new to provide chilled parts in a brake-shoe whichare disposed so that they will contact with or be located opposite tothat portion of the wheel which received the greatest wear by contactwith the rail.

The use of chilled parts in the manner I have described will provide abrake-shoe of great strength and durability.

In Figs. 4: and 6 of the drawings I have shown the rib E, which isprovided on the back of the brake-shoe for attachment to the brakehead.I have also shown two different forms of brake-shoes in these drawingswhich appear to be sufficient for the purpose of fully disclosing theinvention, but it will be understood, of course, that the improvementsmay be embodied in brake-shoes of any kind not inconsistent with thepurposes of the invention.

It will be noted in Figs. 2 and 6 more especially that the contour ofthe wearing-surface of my shoe does not coincide exactly with that ofthe wheel tread and flange, or, in other words, that the chilled portionpractically spans between the tread and flange of the brake-shoe overthe areas of maximum and proportionate wear and does not make contacttherewith. This condition, however, to the fullest extent exists onlywhen the shoe is first applied to the wheel, the length of spangradually lessening as the shoe wears, until finally the contour of theshoe and wheel will actually correspond. This feature is important inorder to avoid detriment to the full effectiveness of the brake-shoeswhen first applied, which might result from carelessness or theexigencies of chilling, when the chilled portion might otherwise servefor some time to prevent the application of the full wearing-surface ofthe shoes to the wheels when first applied, and consequently prevent themaximum braking effect of the shoe being brought into play.

I am aware that changes and variations in the form and proportion of thedifferent parts of my improved brake-shoe may be made without departingfrom the spirit or sacrificing the advantages of the invention, and Iwould therefore have it distinctly understood that I reserve to myselfthe right to make all such changes as fall within the spirit and scopeof the invention.

Having thus fully described my invention, what I claim, and desire tosecure by Letters Patent, is

1. A brake-shoe composed of cast metal having chilled parts in itswearing-surface so disposed as to contact only with that portion of thewheel which contacts with the rail, substantially as described.

2. A cast-metal brake-shoe having a composite integral wearing-facecomposed of unchilled cast metal, chilled cast metal and parwith therail, that portion of the shoe between such continuous wearing surfacesbeing chilled so as to leave a substantially uniform wearing-surface ofchilled metal over the area of maximum wear of the rail upon the Wheel,

approximately from a to a, and gradually decreasing wearing-surfaces ofchilled metal between said uniform chilled portion and the saidcontinuous wearing-surfaces, approximately from a to b and a to b,substantially as described.

4. A brake-sh0e composed of soft metal having chilled parts located inthe wearingsurface of said shoe opposite that portion of the wheel whichcontacts with the rail, said chilled parts being substantially uniformopposite the area of maximum wear of the wheel and gradually reducedfrom said uniform portion at each side to approximately a point Wherethe wear of the rail upon the wheel ceases, substantially as described.

5. As a new article of manufacture, abrakeshoe having parts of itswearing -surface chilled opposite that portion of the wheel whichcontacts with the rail, said chilled portion being adapted and arrangedto span the area of the wheel worn by contact with the rail when firstapplied to the wheel, substantially as described.

WILLIAM D. SARGENT.

WVitnesses:

M. E. SHIELDS, F. H. DRURY.

